To offer a different perspective from both of your's:
As a Jew who had large amounts of his family on both my father and mother's side murdered in the Holocaust, we regard the Shoah (as it is called in Hebrew) as different.
It was the sole attempt in History where someone wanted to wipe out all Jews in existence.
There have been other examples of mass murder against Jews, many pogroms, but this was different.
There have been for some years a Holocaust Memorial Day in Israel, and another two days in our religious lunar calendar when we remember the dead of the Holocaust.
But the international calendar/community in 1996 subsequently added this Holocaust Memorial Day of 27 January.
For all victims of the Nazi violence.
This act of remembrance includes the many millions of others people of other faiths/beliefs who were murdered by the Nazis.
They are not less important than Jews, not less worthy or anything like that, and they are very much remembered by us and others and written about in numerous plays, films, books etc.
It also includes the many millions who have been murdered in mass slaughter since...Cambodia and Rwanda are the examples which I most readily think of.
Now here comes the controversial point.
By you writing on Facebook "But what about the others millions?" it actually reads to me, as denigrating and virtue signalling, as possibly anti-Semitic.
You clearly do not realise this, and having had numerous interacting with
@Cochise on here I have
no belief at all that he is anti Semitic. (And I have no reason to suppose you are either.)
But for a non-Jew to tell a Jew how to relate to Holocaust Memorial Day, will not be well received by us.
We are remembering our families, we are all too aware of what happened under the Nazis.
On a practical level, we have in the UK alone more than one charity from our community and working with other communities, which spend all year educating the entire population on the dangers of extremist hate against people, of and by all religions.